The invention relates to a work platform which is traversed over a downwardly facing surface. More particularly, the invention is in the structure, attached to a work platform with which to carry out work at predetermined areas in a predetermined sequence.
The development of the traversing mechanism for work platforms clinging to the underside of a horizontal surface began as evidenced by U.S. Pat. No. 3,913,752 issued Oct. 21, 1975 to Ward et al. U.S. Pat. Nos. 3,913,452 and 3,889,820 issued with identical specifications. Improvements formed the basis for U.S. Pat. Nos. 4,018,344, 4,018,345 and 4,018,346 which issued with identical specifications.
Although the traversing mechanism is now developed into a relatively trouble-free device, mounting tools on the traversing mechanism to carry out various types of work in a predetermined sequence has not been developed. The work contemplated in the U.S. Pat. Nos. 4,018,344/4,018,345/4,018,346 disclosure was quite limited. In that specification probe tubes 79 are mounted on plates 62. The probe tubes 79 receive eddy current probes for the inspection of tubes of a steam generator.
The probes in tubes 79 perform valid work. They are carried into position by the platform on which they are mounted. However, there is no flexibility in the disclosure when more than one operation is to be carried out at a single position of the platform. Not only is it required to inspect tubes in a steam generator, but it is now required to plug those found to be defective. The plugging operation can involve several different tools and the prior art does not disclose how the tools can be mounted on the platform and brought sequentially to a common work area.